This is a proposal to study the relationship between lead exposure and academic achievement in college students. Most studies of the neurobehavioral effects of lead have focused on performances at the low end of the distribution. There is evidence that lead affects outcome across the entire distribution. This is a retrospective cohort study of subjects whose cognitive function is adequate to gain admission to college. The trend of achievement scores in American students has been biphasic, declining between 1965 and 1975, and then rising. This trend is inversely correlated with both the production of tetraethyl lead (TEL) and air lead levels over the same period. TEL production soared between 1950 and 1970, and then declined to virtually zero. We will use x-ray fluorescence to measure bone lead concentrations in undergraduate college students and test the hypothesis that achievement scores are related to early lead exposure. It will examine the relationship between bone lead levels and college entrance achievement scores and present day neurobehavioral function, including attention, reasoning, language processing, fine motor function, and height, weight and blood pressure. Appropriate covariates will be controlled in the analysis. The toxic level of lead for humans has been steadily revised downward as new data have shown effects at lower levels. Early lead exposure has been shown to have measurable effects on academic performance and neurobehavioral outcome at 18 years of age. Should an effect be found in this study, the spectrum of lead toxicity would be expanded to include subjects with above average function. Data from this study would have implications for educational practice, and for regulation of lead from all sources.